Some More Advice Please

To be honest, 34 litres is not that much better than 20. But the danger with the 90 litre one is that if any of it overhangs the stand it is likely to damage the tank possibly dumping 90 litres of water on your floor. The 90 litre is the better choice if you want more fish, but you would need a bigger stand, or at the very least you need a piece of thick wood or some such; something that is slightly bigger than the base of the tank so no overhang, and something that won't be damaged by water splashes.
Both of them appear to have trickle filters in the lid. The only problem that can occur is if there's a power cut, the media could dry out. if you are in the house at that time, just float the media in the tank to keep it wet.
And replace the carbon cartridges with sponge. Carbon is a hangover from the old days and isn't needed full time.

As for the tank you already had, the 34 litre tank won't be able to have any true cold water fish (ie goldfish) and again it is too small for most temperate fish.

What species are the six fish you currently have?



When you say you are using bottled water, what exactly do you mean? If it's water from the supermarket, you would have to use the same brand at every water change as different brands will have a different mineral content. But if you mean bottles of RO water from the fish shop, you need to add minerals (remineralisation salts) to that. There are no fish in the aquarium trade that can survive in pure water.

Sorry to hear you have problems with your back but have you thought about just keeping the bottles from your bottled water and re-filling them with fresh tap water (with added dechlorinator of course) Then you could either warm or cool to desired temperature. Would save you lugging them home from the shop too.

I'm no expert and am new to this site myself so not even sure if I should be posting this but hope it helps and am sure the experts will put me right if not good advice 

Thanks to Susie & Sue for your replies. I use bottled water, the area I live in has very hard water, and I can get 2 x 5 litre bottles of water for £1.80, so I could change the whole tank (not that I would) for £3.60. I am changing 25% of water every two weeks as I read in the Aqua Style Online Manual, that I downloaded. If that is not right please tell me. Many thanks again Paul.

Bottled water isn't called "Mineral Water" just for effect... Well sometimes it may be so, but it is generally because it contains... well, "Minerals"! Depending upon the exact minerals, these may be the exact minerals that tap-water contains that we call "Hardness".  So, as Sue says, it's not just a matter of remaining "brand-loyal" but in choosing a suitable brand in the first place. Some brands may be harder than your tap-water!

If you're talking about the BRITA water filter system then (from their website):

"The BRITA water filter cartridge is filled with cation exchangers. These replace positively charged ions such as calcium, magnesium, lead, copper with positively charged hydrogen ions"

So it will lower the GH and pH, and perhaps use up all your buffering capacity too. As the filter gets 'used up' over the weeks then this effect will not be a constant and will change a lot when a new cartridge is put in, and consistency of water conditions is vital for fish health.

I wouldn't use it, myself.

I was just wondering if that might be a way to reduce my water hardness further down the line purely out of curiosity.  I have ph 8.2 and very hard water.  I need to invest in kh and gh testers so might do my own experiment! I was thinking if I used that mixed with tap water.  Hmmm. As you say though Colin it might vary considerably throughout the filter life.